Re: On Bug 972 - tag does not work in git fetcher

[Richard Purdie <richard.purdie@linuxfoundation.org>]

On Wed, 2011-04-20 at 15:51 +0800, Yu, Ke wrote:
> I get the root cause of bug 972
> (http://bugzilla.pokylinux.org/show_bug.cgi?id=972) , and want to get
> your comments on how to fix the bug.
> 
> the culprit of this bug is commit
> http://git.pokylinux.org/cgit/cgit.cgi/poky/commit/?id=5920e85c561624e657c126df58f5c378a8950bbc :
> "
> bitbake/fetch2/git: Ensure unresolved branches are translated into
> revisions
> 
> Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
> 
> diff --git a/bitbake/lib/bb/fetch2/git.py b/bitbake/lib/bb/fetch2/git.py
> index 6bcc4a4..f05a360 100644
> --- a/bitbake/lib/bb/fetch2/git.py
> +++ b/bitbake/lib/bb/fetch2/git.py
> @@ -72,7 +72,8 @@ class Git(FetchMethod):
>          ud.basecmd = data.getVar("FETCHCMD_git", d, True) or "git"
>  
>          for name in ud.names:
> -            if not ud.revisions[name] or ud.revisions[name] == "master":
> +            # Ensure anything that doesn't look like a sha256 checksum/revision is translated into one
> +            if not ud.revisions[name] or len(ud.revisions[name]) != 40  or (False in [c in "abcdef0123456789" for c in ud.revisions[name]]):
>                  ud.revisions[name] = self.latest_revision(url, ud, d, name)
>  
>          ud.localfile = ud.clonedir
> "
> with this commit, tag is treated as invalid revision since it is not
> sha256 checksum, so tag become unusable. 
> 
> To fix it,  one option is to revert this commit, another option is to
> check if ud.revisions[name] is tag. I prefer the first option to
> revert this commit, because if user set incorrect revision, reporting
> error to user would be better.  In this case user have chance to fix
> it. the above commit actually hide the error from user which sound not
> good.
> 
> On the other hand, I don't remember the purpose of this commit, so
> want to get your comment to make sure not breaking other things.

The reason for the change was because there were problems being able to
detect if the checkout needed updating or not. To correctly detect that
we need a sha256 ID in the revisions field else need_update() doesn't
work correctly amongst other problems.

The real problem is that we're having a hard time figuring out if that
field refers to a tag or a branch, "master" is the latter for example.
The question is then whether we're happy to take the local value in any
local checkout or whether we want to check the upstream repository in
case its changed. Currently we play it safe and use ls-remote to figure
it out but that means network access.

I think what we need to do is if this is a name, we should, set
ud.branches[name] to be ud.revisions[name] (i.e. the tag) and treat it
like a branch name for the purposes of the ls-remote command. It won't
be perfect as it requires network access to resolve it but it should get
the tag parameter working again. So the code would become:

            if not ud.revisions[name] or len(ud.revisions[name]) != 40  or (False in [c in "abcdef0123456789" for c in ud.revisions[name]]):
                ud.branches[name] = ud.revisions[name]
                ud.revisions[name] = self.latest_revision(ud.url, ud, d,  name)

Cheers,

Richard